the pine tree exhibits characters of the same important order. In bringing this work, therefore, before the public, I am really endeavouring to place before them a scientific research in a popular manner. In so doing, however, I have not merely described my own experiments, but have also given particulars of those of all others who have worked upon the subject, and have incorporated the results in a number of chapters, which deal with a variety of questions more or less intimately concerned with Nature's Hygiene. Each chapter will be found to form a complete essay in itself, and thus the book combines the features of a continuous study of some processes of Nature's chemistry and hygiene, and of a series of articles on scientific subjects. Wherever an educated public is to be found, there must also exist a demand for popular scientific literature; and it is towards feeding such a demand that I have ventured to contribute this work, trusting it may not be received altogether without favour. CHARLES T. KINGZETT. 12, AURIOL ROAD, WEST KENSINGTON, W. March 31st, 1880. CONTENTS The occurrence of Oxygen, Ozone, and Peroxide of Hydrogen in nature; the processes by which they are produced, and their further pro- perties, particularly those relating to the phenomena of respiration PAGE Studies of the processes of chemical oxidation, slow-combustion (decay or eremacausis), and putrefaction; their connection with the purity Infectants and contagious disorders; the liability to contagion ; embracing also a description of the germ and other theories of infectious disease, and the connection of epidemics with the process of putre- Antiseptics and disinfectants considered as agents intended to arrest and prevent the spread of epidemics; their properties and modes of A description of the essential oils and perfumes as natural products, their atmospheric oxidation in nature, the products which are thus formed, and the artificial imitation of the process; with A study of the antiseptic and disinfecting properties of those natural products which are formed in the atmosphere by the oxidation of NATURE'S HYGIENE. CHAPTER I. HISTORICAL NOTES ON OXYGEN, HYDROGEN, WATER, OZONE, PEROXIDE OF HYDROGEN AND ANTOZONE. IN N the early days of the Royal Society, when its meetings were held at Oxford, the Hon. Robert Boyle directed the attention of its members to a number of interesting experiments which he, together with his assistant Dr. Hooke, had made upon ordinary air. Among these observations he showed that animals which were confined in a limited volume of air died after a short time. John Mayow, who attended these meetings, being attracted by the interest of the subject, continued the research thus originated by Boyle and Hooke. He ascertained (1674) that in breathing, animals do not consume the whole of the air which is inspired, and that, indeed, the air consists of two gases, one of which is of no direct use in sustaining life. This gas we now know as "nitrogen." It will be seen that Mayow had, as a matter of fact, discovered "oxygen" gas, although in a negative sort of way; but owing to the erroneous views then prevalent, his discovery was allowed to be forgotten, or nearly so, for a hundred years. Then Priestley, who occupied himself with continued. observations upon gases, succeeded-it may almost be said accidentally-not only in re-discovering oxygen, but also at the same time in making it from a solid substance. It will be remembered by all students of chemical history that, in 1774, Priestley obtained this gas by exposing the red oxide of mercury to a high temperature, and it further appears that Scheele (a Swedish apothecary of famous memory) made the same discovery both simultaneously and independently. Priestley not merely collected oxygen gas, but he ascertained also its powers to support combustion and maintain life. At that time he wrote, "Who can tell whether this pure air may not at last become a fashionable luxury? As yet, only two mice and myself have had the privilege of breathing it."* In spite of all this, he persisted in calling oxygen "dephlogisticated air," and very imperfectly understood his own results. The Parisian Lavoisier (born 1743) was a man of his day. After revolutionising chemical science he himself was sacrificed to a political revolution. He introduced the balance into chemistry, and whereas Priestley had obtained oxygen and mercury from the red oxide, Lavoisier reconstructed the compound *"Short History of Natural Science," p. 234. Buckley. |